This application claims the benefit of Japanese Patent Applications P2001-313782 filed Oct. 11, 2001, and P2002-199004 filed Jul. 8, 2002, the entireties of which are incorporated herein by reference.
1. Field of the Invention
The invention relates to a ceramic laminated article, a method of producing the same and a ceramic laminate.
2. Related Art Statement
A corrosive gas at a high temperature is discharged from a reaction system for performing chemical vapor deposition (CVD) process. It is necessary to discharge the corrosive gas from the system only after the gas is diluted and cooled. Thus, a discharge gas tube that is anti-corrosive against such corrosive gas at a high temperature is needed.
The inventors have investigated various kinds of materials, however, and finally found few materials that are resistive against the corrosive gas at a high temperature flowing in the discharge tube. They have therefore investigated a technique for lining the inner wall surface of the discharge tube with a CVD film such as a silicon carbide film. They have tried to give the discharge tube an anti-corrosion property against the corrosive gas at a high temperature flowing therein by forming the film.
The inventors further investigated the technique and encountered the following problems. That is, a corrosive gas flowing through the discharge tube has a high temperature. It is therefore desired to reduce the temperature during a shorter time period to prevent the corrosion of the film formed on the inner wall surface of the discharge tube. However, as the flow rate of the gas flowing through the discharge tube is large, it becomes difficult to remove a sufficient amount of heat from the corrosive gas by means of thermal exchange with the atmosphere outside of the discharge tube. The corrosion rate of the film may thereby be accelerated. It is thus necessary to diffuse or supply a cooling fluid over a large area of the discharge tube, so as to improve the efficiency of thermal exchange between the corrosive gas and the fluid. Furthermore, in a planar member having a large surface area, such as a cooling trap having a large bottom surface, anti-corrosion property and efficient thermal exchange are needed. In other words, it is necessary to supply a cooling medium into a hollow formed under a film to preserve the anti-corrosion property of the cooling trap and improve the efficiency of the trap of aggregations.
An object of the present invention is to provide a ceramic structure for improving endurance against a corrosive substance and to diffuse and supply a fluid over a larger area of the structure.
Another object of the present invention is to provide a novel process of producing a structure having a ceramic film by means of chemical vapor deposition.
The present invention provides a ceramic laminated article comprising a ceramic sintered body and a ceramic film formed on the sintered body by chemical vapor deposition. A hollow is defined by the sintered body and ceramic film, and a hole in communication with the hollow and the outside space of the article is formed in the article.
The present invention further provides a method of producing a ceramic laminated article. According to the method, a laminate is prepared having a ceramic sintered body with a recess formed therein, a filling material filled in the recess and a ceramic film is formed on the sintered body so as to cover the filling material. The ceramic film is formed by chemical vapor deposition in the laminate, and a hole in communication with the recess and with the outside is formed in the laminate. The laminate is subjected to a heat treatment to dissipate the filling material through the hole.
The present invention further provides a ceramic laminated article obtained by the above method.
The present invention further provides a ceramic laminate having a ceramic sintered body with a recess formed therein, a filling material filled in the recess and a ceramic film formed on the sintered body so as to cover the filling material. The ceramic film is formed by chemical vapor deposition. The laminate has a hole communicating with the recess and with the outside formed therein.
These and other objects, features and advantages of the invention will be appreciated upon reading the following description of the invention when taken in conjunction with the attached drawings, with the understanding that some modifications, variations and changes of the same could be made by a skilled person in the art.